1. Field of the Invention
The present invention relates to a mask which is used in the photolithography process as one of the process of manufacturing semiconductor integrated circuits, and an device for managing the mask.
2. Description of the Related Art
A mask is an original plate of a circuit pattern which is used to transfer therethrough a circuit pattern of a semiconductor integrated circuit on a wafer. For the purpose of managing the mask, in addition to a circuit pattern, the information such as a name of a semiconductor integrated circuit which will be manufactured by utilizing the mask (or a drawing number of a mask), a name of a possessor, and a calendar in manufacture of the mask is entered in the mask.
In manufacture of the mask, such information is entered in a peripheral portion of the mask in which no circuit pattern is formed. However, since the area of the peripheral portion of the mask is relatively small, it is difficult to enter any information therein. For this reason, the detailed information for each of the masks is retained in a host computer or a document. In addition to the information described above, any relevant information regarding the masks, such as a drawing number of a mask blank, inspection conditions, inspection results, existence and non-existence of mask repair and mask repair positions, a drawing number of a pellicle, cleaning conditions and the number of cleaning, phase differences and the like may be included. In addition, in order to judge the life of the pellicle which is used for protecting the mask and to diagnose any defects of the mask, information relating to the amount of exposure, the target CD (crystal dimension) data, the number of exposure (the total amount of exposure energy), the inspection conditions and the inspection results in periodical inspection, and the yield of LSIs which were manufactured using the masks may be included.
However, conventionally, since the masks and the information thereof are separately managed and also the number of masks is enormous, it is difficult to sufficiently manage the masks.